com.saxonica.schema.fsa

## Class Edge

- java.lang.Object
- - com.saxonica.schema.fsa.Edge

-     public class Edge
      extends Object

  Internal class to represent the data associated with a transition: the element that triggers the transition, and the new state that results from the transition.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `Edge.MaxOccursParticle`
    `static class` | `Edge.MaxOccursTerm` Special singular Term identifying a transition to be used when the maxOccurs value of a counting state is reached.

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static Edge.MaxOccursParticle` | `MAX_OCCURS_PARTICLE` Special singular Term identifying a transition to be used when the maxOccurs value of a counting state is reached.

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `Edge()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Particle` | `getParticle()` Get the element or wildcard particle causing this transition
    `AutomatonState` | `getTargetState()` Get the (fixed) state that is the target of this edge
    `Term` | `getTerm()` Get the element or wildcard particle causing this transition
    `State` | `makeTransition(State previousState)` Get the dynamic state that results from a transition using this edge, updating any counters that need to be updated
    `String` | `matches(Edge de, SchemaCompiler compiler)` Test whether edges in two different finite state machines match each other.
    `void` | `serialize(SchemaModelSerializer serializer)` Serialize this Edge as part of the serialization of a schema component model
    `void` | `setParticle(Particle particle)` Set the element or wildcard particle causing this transition
    `void` | `setTargetState(AutomatonState targetState)` Set the state resulting from this transition
    `void` | `setTerm(Term term)` Set the element or wildcard particle causing this transition

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### MAX_OCCURS_PARTICLE

          public static final Edge.MaxOccursParticle MAX_OCCURS_PARTICLE

      Special singular Term identifying a transition to be used when the maxOccurs value of a counting state is reached. This enables content models like a(2,2)a to be treated as non-ambiguous. See test case modelGroups mg005.

  - ### Constructor Detail

    - #### Edge

          public Edge()

  - ### Method Detail

    - #### setTargetState

          public void setTargetState(AutomatonState targetState)

      Set the state resulting from this transition
      Parameters:
        `targetState` - the state at the end of this edge

    - #### getTargetState

          public AutomatonState getTargetState()

      Get the (fixed) state that is the target of this edge
      Returns:
        the state at the end of this edge

    - #### makeTransition

          public State makeTransition(State previousState)
                               throws ValidationException

      Get the dynamic state that results from a transition using this edge, updating any counters that need to be updated
      Parameters:
        `previousState` - the previous dynamic state before making this transition
      Returns:
        the dynamic state that results from applying this transition
      Throws:
        `ValidationException` - if this transition is not possible because the occurrence limits are violated

    - #### setTerm

          public void setTerm(Term term)

      Set the element or wildcard particle causing this transition
      Parameters:
        `term` - the term that causes this transition

    - #### getTerm

          public Term getTerm()

      Get the element or wildcard particle causing this transition
      Returns:
        the term that causes this transition

    - #### setParticle

          public void setParticle(Particle particle)

      Set the element or wildcard particle causing this transition
      Parameters:
        `particle` - the particle that causes this transition

    - #### getParticle

          public Particle getParticle()

      Get the element or wildcard particle causing this transition
      Returns:
        the particle that causes this transition if known, otherwise null

    - #### matches

          public String matches(Edge de,
                       SchemaCompiler compiler)

      Test whether edges in two different finite state machines match each other. This is called while establishing whether one type subsumes another.

      From Thompson & Tobin 2003: an edge BE matches another edge DE iff one of the following three conditions holds: (1) they are labelled as element declarations with the same expanded name; (2) BE is labelled with a wildcard and DE is labelled with an element declaration in a namespace allowed by the wildcard; (3) BE and DE are both wildcards and DE's label is an intensional subset of BE's. In case (3) we add the rule, not in Thompson and Tobin, that the processContents of DE must be at least as strong as the processContents of BE.

      It is also necessary that the types of B and D are compatible, and that their nillability is compatible, and that their value constraints are compatible, and that the disallowed substitutions of D is a superset of those of B.

      Parameters:
        `de` - the edge in a finite state machine representing a derived type, and which corresponds to this edge in the finite state machine for the base type
        `compiler` - user for error reporting
      Returns:
        null if the edges match, or a string explaining the reason for the non-match if not.

    - #### serialize

          public void serialize(SchemaModelSerializer serializer)
                         throws XPathException

      Serialize this Edge as part of the serialization of a schema component model
      Parameters:
        `serializer` - object that formats the model output
      Throws:
        `XPathException` - if a serialization error occur

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